Using the Entity$-$Relationship model $($extended if necessary with generalization$),$ build a conceptual schema that captures the following natural language description of the requirements of a bus company. Express your schema using an ER diagram; it must be syntactically correct and readable.

Make clear what reasonable assumptions, if any, you are making. State concisely $($in English, but referring to the elements of your schema$)$ any constraints that cannot be expressed in the ER schema. Include all cardinalities. Do not submit separate schema fragments.

Notation: You must make Use the notation developed in class. Add an asterisk on relationship cardinalities to indicate that it is assumed.

A city is identified by its name and state; we also need to store its population and the names of popular tourist attractions. A city must have at least one bus stop. Each bus stop is located in a city and has a number that is unique within that city, but may not be unique in general. It is important to keep track of the bus stops that have restaurants because routes using them as intermediate stops always allow passengers at least an hour. Each route served by the company has a unique route number. A route has a starting stop

and ending stop $($that is different from the starting stop$),$ and can go through several intermediate stops. The number of miles covered in a route is also recorded. For every intermediate stop of a route, the arrival and departure times are known; for the start stop, only the departure time is known, and for end stops, only the arrival time. The company operates a fleet of buses. Each bus is identified by a unique bus number as well as by a unique VIN $($vehicle identification number$).$ We also need to store the date of purchase for each bus. It is crucial to keep track of the operational status of every bus. Some

buses are small vans which are restricted to routes of $200$ miles or less; for these, it important to remember their capacity and whether or not they have any space for carrying luggage. For each driver employed by the company, it is necessary to keep track of their unique identification number, license number, name, and the number of years they have been employed by this company.

The company only cares about the assignments of drivers to buses and routes for the current day: no route starts before $0200$ hours $(2$ am$)$ and all end before $2359$ hours $(1159$ pm$)$; past and future assignments can be ignored. It can assign any driver to any bus on any route; however, it ensures that every driver uses a fixed bus per route.